fix: keep keyboard focus when changing wallet source in payment popup

https://stackoverflow.com/a/76367322/8301867

lib/widgets/payment_popup.dart

@@ -145,16 +145,14 @@ void paymentPopup(BuildContext context, String toAddress, String username) {
                       ),
                       const SizedBox(height: 10),
                       Consumer<SubstrateSdk>(builder: (context, sub, _) {
-                        // TODO: about keyboard dismiss issue, should try this: https://stackoverflow.com/a/76352647/8301867
                         return DropdownButton(
                           dropdownColor: const Color(0xffffeed1),
                           elevation: 12,
                           key: dropdownKey,
                           value: defaultWallet,
-                          // onTap: () async {
-                          //   await Future.delayed(const Duration(milliseconds: 10));
-                          //   amountFocus.requestFocus();
-                          // },
+                          onTap: () {
+                            FocusScope.of(context).requestFocus(amountFocus);
+                          },
                           selectedItemBuilder: (_) {
                             return myWalletProvider.listWallets
                                 .map((WalletData wallet) {
@@ -268,7 +266,13 @@ void paymentPopup(BuildContext context, String toAddress, String username) {
                         ],
                       ),
                       const SizedBox(height: 10),
-                      TextField(
+                      Focus(
+                        onFocusChange: (focused) {
+                          setState(() {
+                            FocusScope.of(context).requestFocus(amountFocus);
+                          });
+                        },
+                        child: TextField(
                           textInputAction: TextInputAction.done,
                           onEditingComplete: () async =>
                               canValidate ? await executeTransfert() : null,
@@ -305,8 +309,8 @@ void paymentPopup(BuildContext context, String toAddress, String username) {
                             filled: true,
                             fillColor: Colors.transparent,
                             focusedBorder: OutlineInputBorder(
-                            borderSide:
-                                BorderSide(color: Colors.grey[500]!, width: 2),
+                              borderSide: BorderSide(
+                                  color: Colors.grey[500]!, width: 2),
                               borderRadius: BorderRadius.circular(8),
                             ),
                             contentPadding: const EdgeInsets.all(20),
@@ -317,6 +321,7 @@ void paymentPopup(BuildContext context, String toAddress, String username) {
                             fontWeight: FontWeight.w600,
                           ),
                         ),
+                      ),
                       const Spacer(),
                       SizedBox(
                         width: double.infinity,